Method for irradiating cells

ABSTRACT

An apparatus for irradiating cells with ultraviolet light including an ultraviolet light source and an outer cylinder that surrounds the ultraviolet light source. Hollow tubing is helically wrapped around the outer peripheral surface of the outer cylinder. The hollow tubing is adapted to transport suspended cells over the outer surface of the outer cylinder so that the cells can be irradiated by the ultraviolet light source. An inner cylinder can be positioned inside the outer cylinder, between the ultraviolet light source and the outer cylinder. The apparatus can include an arrangement for ventilating the apparatus during use in order to maintain a substantially constant temperature.

This application is a continuation of Application Ser. No. 07/948,420,filed Sep. 22, 1992, abandoned which is a divisional application ofapplication Ser. No. 07/378,994, filed Jul. 12, 1989, U.S. Pat. No.5,150,705.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for irradiating fluids.More particularly, the present invention concerns an apparatus forpermitting cells to be irradiated by an ultraviolet light source.

The transplantation of cells into an allogeneically different recipienthas been researched by several medical investigators in an attempt totreat specific medical diseases and disorders. In order to successfullycarry out such a transplantation of cells, it is necessary toimmunosuppress antigen expression and/or recognition of the transplantedcells. In that way, the body's natural tendency to reject thetransplantation of the allogeneic cells can be overcome.

One generally recognized method for immunosuppressing the antigenexpression and recognition of the allogeneic cells is to subject thecells to ultraviolet radiation. The uses of ultraviolet radiation withinthe context of cellular transplantation are discussed in an articleauthored by H. Joachim Deeg entitled "Ultraviolet Irradiation inTransplantation Biology," Transplantation, Vol. 45, No. 5, pp. 845-851,May 1988.

Several other articles have also been written describing specificmethods that have been employed for subjecting transplant cells toultraviolet radiation. For example, in one method, blood diluted in aphosphate buffer was placed in petri dishes and subjected to ultravioletlight for twenty minutes. The light source emitting the ultravioletlight was positioned at a specified distance from the petri dish.However, not all of the experiments utilizing that method wereapparently conducted with the light source positioned at the samedistance from the petri dishes. Hardy, M. A., Lau, H. T., Weber, C.,Reemtsma, K.: "Pancreatic Islet Transplantation: Immuno-alteration WithUltraviolet Irradiation", World Journal of Surgery, Vol. 8, No. 2, pp.207-213, April 1984. Hardy, M. A., Lau, H., Reemtsma, K.: "Prolongationof Rat Islet Allografts With the Use of Ultraviolet Irradiation, WithoutImmunosuppression", Transplantation Proceedings, Vol. 16, No. 3, pp.865-869, June 1984.

In another method, platelets were suspended in a solution, placed in anopen petri dish to a depth of 1.5 mm and subjected to ultraviolet lightirradiation while being continuously shaken. Slichter, S. J., Deeg, H.J., Kennedy, M. S.: "Prevention of Platelet Alloimmunization in DogsWith Systemic Cyclosporine and by UV-Irradiation or Cyclosporine-Loadingof Donor Platelets", Blood, Vol. 69, No. 2, pp. 414-418, February 1987.

An additional method includes placing whole blood which has been dilutedwith Waymouth's minimal medium in petri dishes at a layer thickness of1.5 mm and irradiating the suspension with ultraviolet light for thirtyminutes. Deeg, H. J., Aprile, J., Graham, T. C., Appelbaum, F. R.,Storb, R.: "Ultraviolet Irradiation of Blood PreventsTransfusion-Induced Sensitization and Marrow Graft Rejection in Dogs",Blood, Vol. 67, No. 2, pp. 537-539, February 1986.

Various other articles have been published in addition to those notedabove concerning the use of ultraviolet light irradiation on cells. See,for example, Lindahl-Kiessling, K., Safwenberg, J.: "Inability ofUV-Irradiated Lymphocytes to Stimulate Allogeneic Cells in MixedLymphocyte Culture", Int. Arch. Allergy, Vol. 41, pp. 670-679, 1971;Balsh, J. D., Francfort, J. W., Perloff, L. J.: "The Influence ofUltraviolet Irradiation on the Blood Transfusion Effect", Surgery, pp.243-249, August 1985; Lau, H., Reemtsma, K., Hardy, M. A.: "Prolongationof Rat Islet Allograft Survival by Direct Ultraviolet Irradiation of theGraft", Science, Vol. 223, pp. 607-609, Feb. 10, 1984.

It becomes readily apparent from a review of the above articles that thetechniques and methods presently employed in ultraviolet lightirradiation for transplant and transfusion related procedures sufferfrom several drawbacks and are susceptible to improvement. Inparticular, there is no uniformity among the various techniquescurrently used. In fact, the nature of the techniques is such that evenwith respect to each individual test, uniformity is difficult tomaintain. For example, since the cellular suspension is placed in petridishes and then subjected to irradiation in the various methods,uniformity can only be maintained if the distance between the cellularsuspension and the light source is kept constant. Of course, it israther evident that such distance depends upon the amount of cellularsuspension placed in the petri dish and, clearly, the amount of cellularsuspension in a petri dish can be a difficult factor to keep constant.Cells which are placed and suspended in a given volume of solution beginto settle to the bottom of the petri dish over time. Thus, the number ofcells in suspension during irradiation tends to decrease throughout theirradiation process.

A related problem that arises when the cellular suspension is irradiatedin petri dishes according to the above procedures is that it isdifficult to subject all of the cells in the cellular suspension to thesame amount of ultraviolet irradiation. That is due in part to the factthat the cellular suspension is somewhat stagnant in the petri dishes.That is to say, the cells in the suspension do not move throughout thesuspension but rather, maintain their relative positions within thesuspension. As a consequence, cells on the surface of the cellularsuspension located closer to the ultraviolet light source are subjectedto a different amount of irradiation than underlying cells in thecellular suspension. Although one of the foregoing articles mentionsshaking the petri dish during irradiation, that technique would not beentirely effective in overcoming the aforementioned problem.

For example, shaking a petri dish that is not covered in order tosubject the cells to movement results in an increase in the amount ofevaporation of the cellular suspension. On the other hand, covering thepetri dish prior to shaking may not be an effective solution because thematerial from which the cover is made can affect, and significantlyreduce, the amount of irradiation received by the cellular suspension.Thus, a difficult calibration procedure is necessary.

Another drawback associated with the techniques currently employed inultraviolet light irradiation for transplant/transfusion relatedprocedures is that there is no stability with respect to other factorsaffecting the irradiation process. For instance, the temperature in thearea surrounding the irradiation process can have a significant effectupon the intensity of the irradiation process. Accordingly, if theambient temperature is not maintained at a particular level, consistentand reliable results will not be possible with respect to successiveirradiation processes.

Similarly, during the initial hours of operation, the output from theultraviolet light source can vary in fluorescent lamp systems. Thus, acellular suspension irradiated during the initial hours of operationwill be subjected to a different amount of irradiation than cellularsuspensions that are irradiated later.

OBJECTS AND SUMMARY OF THE INVENTION

As can be seen from the foregoing discussion, a need exists for anapparatus and method for irradiating cells that can overcome thedrawbacks associated with the techniques presently employed. It is,therefore, an object of the present invention to provide an apparatusand method for irradiating cells with ultraviolet light that permitsuniformity with respect to the manner in which the cells in the cellularsuspension are irradiated.

It is also an object of the present invention to provide an apparatusand method for irradiating cells with ultraviolet light that permitsstability with respect to the operation of the apparatus. Providing anapparatus and method that can meet the two foregoing objectives isdesirable because after the apparatus has been calibrated to ensure thatthe cells in a particular amount of cellular suspension will besubjected to a particular amount of ultraviolet irradiation in a givenamount of time, one can be assured that subsequent operations of theapparatus will provide substantially the same results as those expectedfrom the calibration of the apparatus.

It is an additional object of the present invention to provide anapparatus and method for irradiating cells that is relatively simple andinexpensive to manufacture, and relatively easy to operate.

It is a further object of the present invention to provide an apparatusand method for irradiating cells that is able to inhibit thetransmission of ultraviolet light having a particular wavelength so thatthe cells in the cellular suspension are not subjected to suchultraviolet light. In that way, the potentially harmful effects ofultraviolet light having a particular wavelength can be avoided.

Those and other objects that will become more apparent from thefollowing description, including the appended claims and the drawings,are achieved through the apparatus and method according to the presentinvention.

The apparatus includes an ultraviolet light source and an outer cylinderthat surrounds the ultraviolet light source. An arrangement is providedfor carrying suspended cells that are to be subjected to ultravioletirradiation. Preferably, that arrangement includes hollow tubing that iswrapped helically around the outer peripheral surface of the outercylinder.

In addition to the above features, the apparatus can also include aninner cylinder that is positioned between the outer cylinder and theultraviolet light source. The apparatus can include an arrangement forfiltering the ultraviolet light so that ultraviolet light having aparticular wavelength is inhibited from passing through the inner and/orouter cylinders. Also, the apparatus can include an arrangement forventilating the system in order to maintain a substantially constanttemperature.

The method for irradiating potential transplant cells with ultravioletlight according to the present invention includes the steps of feeding acell suspension into an inlet end of a transport arrangement fortransporting and guiding the cell suspension, transporting the cellsuspension over at least a portion of an outer surface of an outercylinder, irradiating the suspended cells with ultraviolet light from anultraviolet light source that is positioned inside the outer cylinderand collecting the cell suspension after irradiation in a collectionreservoir as the cell suspension exits an outlet of the transportarrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will be described ingreater detail with reference to the accompanying drawings, wherein likeelements bear like reference numerals and where:

FIG. 1 is a front view of the apparatus for irradiating cells accordingto a preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view of a preferred embodiment of anapparatus according to the present invention taken along the sectionalline 2--2 in FIG. 1;

FIG. 3 is a cross-sectional view of a preferred embodiment of anapparatus according to the present invention taken along the sectionalline 3--3 in FIG. 2;

FIG. 4 is a right end view of a preferred embodiment of an apparatusaccording to the present invention;

FIG. 5 is a left end view of a preferred embodiment of an apparatusaccording to the present invention therefor; and;

FIG. 6 is a cross-sectional view similar to FIG. 2 except illustrating adifferent placement for the filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIG. 1, the apparatus 20 for irradiating cellsincludes a hollow outer cylinder 22 that extends in a longitudinaldirection. Hollow tubing 24 is wrapped helically around the outerperipheral surface of the outer cylinder 22. The helically wrappedtubing 24 extends along substantially the entire longitudinal extent ofthe outer cylinder 22. It will be noted that in the preferredembodiment, the tubing 24 is wound around the outer peripheral surfaceof the first cylinder 22 in such a manner that each successive wrap ofthe tubing 24 closely abuts the previous wrap. Hence, a tightarrangement of the helically wound tubing 24 is obtained.

As seen in FIG. 2, a hollow inner cylinder 26 is positioned inside theouter cylinder 22. The inner cylinder 26 also extends in thelongitudinal direction and is substantially parallel to the outercylinder 22. The inner cylinder 26 is spaced from the outer cylinder 22so that a space 28 exists between the inner surface 30 of the outercylinder 22 and the outer surface 32 of the inner cylinder 26.

Located centrally in the apparatus 20 is an ultraviolet light source 34.The ultraviolet light source 34 also extends in the longitudinaldirection and is substantially parallel to the outer cylinder 22 and theinner cylinder 26. Thus, both the outer cylinder 22 and the innercylinder 26 surround the ultraviolet light source 34. The ultravioletlight source 34 is spaced from the inner cylinder 26 so that a space 36exists between the inner surface 38 of the inner cylinder 26 and theouter surface 40 of the ultraviolet light source 34. The ultravioletlight source 34, the inner cylinder 26 and the outer cylinder 22 are allof substantially the same length.

Turning to FIG. 3, the apparatus 20 further includes a first seal member42 and a second seal member 44. The first seal member 42 serves to sealthe first end 46 of the outer cylinder 22 while the second seal member44 serves to seal the second end 48 of the outer cylinder 22. The firstseal member 42 is positioned with respect to the outer cylinder 22 suchthat the end face at the first end 46 of the outer cylinder 22 abutsagainst the inner surface 50 of the first seal member 42. Similarly, thesecond seal member 44 is positioned with respect to the outer cylinder22 such that the inner surface 52 of the second seal member 44 abutsagainst the end face of the outer cylinder 22 that is located at thesecond end 48 of the outer cylinder 22.

It can be further seen from FIG. 3 that the inner cylinder 26 issubstantially the same length as the outer cylinder 22. Accordingly, theinner face 50 of the first seal member 42 abuts against the end face ofthe inner cylinder 26 that is located at the first end 54 of the innercylinder 26. Likewise, the end face of the inner cylinder 26 located atthe second end 56 of the inner cylinder 26 abuts against the innersurface 52 of the second seal member 44.

Supporting members 58 are integrally connected to each of the sealmembers 42, 44. The supporting members 58 serve the purpose ofsupporting the apparatus 20 in a horizontal manner on a horizontalsurface. It is, of course, understood that some other form of supportcan be provided as an alternative to the supporting members 58.

With continued reference to FIG. 3, at least one and preferably aplurality of spaced apart apertures 60 extend radially through the innercylinder 26. The apertures 60 are positioned adjacent the second end 56of the inner cylinder 26 and, preferably, the apertures 60 extend aroundthe entire circumference of the inner cylinder 26. As a result of theabutting arrangement of the first and second seal members 42, 44 withrespect to the inner and outer cylinders 26, 22, and the presence of theapertures 60 extending through the inner cylinder 26, the space 28between the inner and outer cylinders 26, 22 is in fluid communicationwith the space 36 between the inner cylinder 26 and the light source 34.

The first seal member 42 as seen in FIG. 4 includes preferably one firsthole 62 that extends through the first seal member 42 and that ispositioned in such a manner as to communicate the space 36 between theinner surface 38 of the inner cylinder 26 and the outer surface 40 ofthe ultraviolet light source 34 with the atmosphere. As a result of theabutting arrangement of the first seal member 42 and the inner and outercylinders 26, 22, the hole 62 can communicate with the space 36 betweenthe inner cylinder 26 and the light source 34 and the space 28 betweenthe inner and outer cylinders 26, 22 through the previously describedapertures 60. Positioned in the first hole 62 is an inlet port 64. Theinlet port 64 is adapted to be connected to a suitable source of air 66such as a small duct fan. According to that arrangement, the duct fancan blow or suction air through the inlet port 64 and into the space 36through the radially positioned apertures 60.

The first seal member 42 also includes at least one and preferably aplurality of second holes 68 that extend through the first seal member42. The second holes 68 are positioned such that the space 28 betweenthe inner surface of the outer cylinder 30 and the outer surface 32 ofthe inner cylinder 26 is in communication with the atmosphere. Onceagain, since the first seal member 42 is in abutting relation to theinner and outer cylinders 26, 22, the plurality of second holes 68 canonly communicate with the space 28.

The first seal member 42 further includes two additional holes 70through which the tube pins 72 extending from one end of the ultravioletlight source 34 can extend. As can be seen in FIG. 5, the second sealmember 44 also includes two holes 74 through which the two tube pins 76extending from the other end of the ultraviolet light source 34 canextend. In that way, a suitable power source (not shown) can beconnected to the tube pins 72, 76 in order to provide power to theultraviolet light source 34.

Turning once again to FIG. 1, one end of the helically wound tube 24,the inlet end, is connected to a suitable container 78 in which islocated the cellular suspension that is to be subjected to irradiationby the ultraviolet light source 34. The container 78 can be either atransfusion bag or some other type of sterile container that is equippedto filter incoming air, if needed. A variable rate pump 80 is alsoprovided at the inlet end of the helically wound tube 24. The variablerate pump 80 serves to move the cell suspension located in the container78 through the helically wound tube 24.

A collection reservoir 82 is connected to the opposite end of thehelically wound tubing, the outlet end, in order to permit collection ofthe cellular suspension that has been irradiated by the ultravioletlight source 34.

The outer cylinder 22 and the inner cylinder 26 should be manufacturedfrom materials that are well suited for transmitting and filteringultraviolet light. The material from which the inner and outer cylinders26, 22 are manufactured should be capable of transmitting at leastninety percent of the preferred ultraviolet light spectrum. One materialthat has been found to give desirable results is fused silicate glass.That material offers certain advantages over other materials, such as,for example, optical grade plastic, in that the fused silicate glasspossesses greater stability under temperature changes. It should beunderstood, however, that materials other than fused silicate quartz canbe employed so long as the material selected is capable of performingthe intended objective.

For the most part, fluorescent ultraviolet lamp systems emit acombination of U.V.-A, U.V.-B, and U.V.-C light and differ in theirspectral distribution and intensity. For example, a U.V.-B tube emitsmostly U.V.-B light that falls between 280 and 320 nanometers. The sametube, however, also emits to some extent a minimal amount of U.V.-A andU.V.-C light.

Preferably, the ultraviolet light source 34 used in the presentinvention is a U.V.-B medium wave fluorescent tube. Such a tube issuitable because, as mentioned above, it emits an optimal distributionof ultraviolet light within a range of approximately 280 nanometers (nm)to 320 nanometers (nm). That range of ultraviolet light has been foundto be most suitable for irradiating potential transplant cells in acellular suspension. However, as was pointed out previously, the U.V.-Bmedium wave fluorescent tube emits minimal but additional amounts ofultraviolet light over a range of wavelengths outside the 280-320nanometer range. Ultraviolet light ouside the 280-320 nanometer rangehas been found to be not entirely suitable for irradiating potentialtransplant cells.

In order to address that concern, a filtering arrangement can beprovided with respect to the inner and/or outer cylinders in order toinhibit the transmission of ultraviolet light having the undesiredwavelength. The use of an ultraviolet light source that is capable ofemitting ultraviolet light having the desired spectral distribution andrange is particularly well adapted to be used in conjunction with afiltering arrangement because the filtering arrangement would permit theportion of the ultraviolet light having the desired wavelength to passthrough the inner and outer cylinders while also allowing theundesirable and potentially harmful portion of the ultraviolet lightoutside of the U.V.-B range to be filtered prior to reaching thehelically wound tube and the cellular suspension contained therein.

One portion of the spectral range of ultraviolet light that has beenfound to be undesirable is ultraviolet light in the U.V.-C range. It hasbeen determined that ultraviolet light in the U.V.-C range is notparticularly well suited for irradiating cells because of its highenergy and short wavelength properties.

In one embodiment, the above-described filtering arrangement can takethe form of a film that is coated on the outer surface 32 of the innercylinder 26. One film that has been found to be particularly well suitedfor inhibiting or blocking the transmission of high energy, shortwavelength U.V.-C light is "KODACEL" TA 401 film manufactured by theEastman Kodak Co. It is preferable that the film be capable ofinhibiting the transmission of U.V.-C light having a wavelength in therange between approximately 200 nanometers and 280 nanometers. While theaforementioned film is preferably positioned on the outer peripheralsurface 32 of the inner cylinder 26, (see reference numeral 90, FIG. 2)it may be desirable to coat the inner surface 30 of the outer cylinder22 with the same type of film (see reference numeral 92, FIG. 6).However, in order to maximize the stability of the film, the filters arepreferably placed away from the ultraviolet light source. A film coatinghaving a thickness of between 0.10 mm and 0.15 mm has been found toprovide desirable results although other thicknesses could be utilizeddepending upon the results desired.

While it is desirable that the high energy, short wavelength U.V.-Clight be filtered in the aforementioned manner in order to avoidirradiation of the cellular suspension by that portion of theultraviolet light, filtering and inhibiting the transmission of U.V.-Alight is not quite as great a concern. That is because the U.V.-A lightis a low energy, long wavelength range of light. As a result, the U.V.-Alight will not have the same potentially harmful effects on the cellularsuspension as the high energy, short wavelength U.V.-C light.

Nevertheless, in order to ensure that the cellular suspension issubjected to only U.V.-B light, a filtering arrangement can be providedfor inhibiting the transmission of U.V.-A light through the inner and/orouter cylinders 26, 22. One particular filtering arrangement that hasbeen found to be effective is the use of a nickel and cobalt sulfatefilter which can be positioned in the aforementioned places in order tofilter U.V.-A light and still transmit U.V.-B light. As an alternative,optical filters of any suitable type can be used so long as the opticalfilter is capable of achieving the desired objective of filtering theportion of the ultraviolet light with which the cellular suspensionshould not be irradiated. Also, anti-reflective coatings can be placedon the inner and/or outer cylinders to improve the transmission ofultraviolet light through the inner and/or outer cylinders.

It is to be understood from the foregoing that a filtering arrangementcan be employed for inhibiting and blocking the transmission of U.V.-Alight and U.V.-C light while permitting the transmission of U.V.-Blight. Further, through the appropriate selection of films and/oroptical filters, only the U.V.-B light having a desired wavelength canbe permitted to irradiate the cellular suspension flowing in the tube24.

The aforementioned filtering arrangement could also be utilized inconjunction with a different ultraviolet light source than thatdescribed above. For example, it may be desirable for other reasons toemploy an ultraviolet light source that emits primarily U.V.-A light,primarily U.V.-C light or a combination of both.

The helically wound hollow tube 24 should preferably be manufacturedfrom material that is adapted to readily transmit ultraviolet light. Onetype of material that has been found to be well suited for transmittingultraviolet light is polypropylene. "EXTREL" polypropylene, and morespecifically EX-50 polypropylene, manufactured by Exxon Chemical Co. hasbeen determined to be desirable.

One of the advantages associated with the apparatus according to thepresent invention is that the apparatus 20 is equipped with aventilation system that is designed to maintain a constant temperaturein the apparatus 20 while the apparatus is in use. Turning to FIG. 3,the ventilation system operates in the following manner. The small ductfan 66, or other suitable source of air, blows air through the inletport 64 and into the space 36 between the inner surface 38 of the innercylinder 26 and the outer surface 40 of the ultraviolet lamp 34. The airis forced toward the second end 56 of the inner cylinder 26, whereuponthe air flows through the plurality of apertures 60 that extend throughthe second cylinder 26. The air then flows, as illustrated by arrows A,toward the holes 68 that extend through the first seal member 42. It canbe seen, therefore, that the continuous flow of air from the duct fan 66or other suitable source of air into the space 36, through the holes 60,through the space 28 and out the apertures 68 provides continuousventilation of the apparatus 20 and ensures that the air in the closedsystem is continuously ventilated.

One of the advantages resulting from the ventilation system according tothe present invention is evident when considered in light of the factthat changes in the ambient temperature can result in up to a sixtypercent variation in the output of the ultraviolet lamp. If theapparatus is initially calibrated based upon results obtained when theapparatus is operated in a particular set of ambient conditions, thelater operation of the apparatus at ambient conditions that aredifferent from those that existed when the apparatus was firstcalibrated will result in the cellular suspension being irradiated by anamount that is at variance with the expected amount. Thus, theutilization of a ventilating system that helps ensure that thetemperature in the apparatus is maintained at a substantially constantlevel will help ensure that the cells in the cellular suspension areirradiated at a desired level and by a desired amount of ultravioletlight.

It is to be understood that as an alternative to the duct fan 66, avacuum or suction pump could be connected to the inlet port 64 in orderto continuously ventilate the closed system. In that alternativearrangement, the vacuum pump would draw air into the space 28 throughthe holes 68 and the air would flow through the apertures 60 that extendthrough the inner cylinder 26, through the space 36 and out the port 64.

Another advantage associated with the ventilation system of the presentinvention concerns the aforementioned use of filters and the like forfiltering and inhibiting the transmission of ultraviolet light having aparticular wavelength. In that regard, the heat produced by theultraviolet light source and the resulting temperature in the apparatus20 can cause the filter surface to warp or shift. Through use of theventilation system, the temperature within the apparatus 20 can bemaintained at a level that is not harmful to the filter surface. Tofurther enhance filter stability, the ventilating holes 68 that vent airbetween the outside air and the space 28 between the inner and outercylinders 22, 26 can be switched with the inlet port 62 if so desired.Also, reverse air flow through use of the aforementioned vacuum orsuction pump can transfer heat faster from the inner and outer cylindersto thereby avoid damaging the filter surfaces. That reverse air flowallows the heat generated by the lamp to leave the system faster becausethe heat is transferred immediately out of the system instead of beingcarried through it.

The variable rate pump 80 could be replaced with other devices that areadapted to perform a similar function. For example, a Harvard variablesyringe pump or any type of adjustable high pressure pumping devicecould be employed for pumping the cellular suspension from the container78 through the helically wound tube 24 and to the collection reservoir82.

The use of an outer cylinder having an outer radius of approximately 24mm and a length of approximately 190 mm as measured between the firstand second seal members 42, 44 in conjunction with hollow tubing 24having an inside diameter of approximately 1.02 mm and an outsidediameter of 2.16 mm will permit approximately 10.84 ml of cellularsuspension to be located in the tubing 24 over the exposure area of theapparatus. The outer radius of the inner cylinder 26 can beapproximately 16 mm. Also, the spacing between the inner and outercylinders 20, 22 and the spacing between the inner cylinder and theultraviolet light source can be approximately 8 mm. Those dimensions andvalues are given only by way of example and are only intended toillustrate the fact that it is necessary to know the dimensions of theouter cylinder and the tubing so that the amount of cellular suspensioncontained in the tubing can be determined for dose calculation purposes,for calibration purposes, and for purposes of obtaining consistentresults.

In order to ensure that the cells in the cellular suspension which arepumped through the helically wound tubing are irradiated by a known ordeterminable amount of ultraviolet light, it is important, and alsoessential, that the apparatus 20 be calibrated. As a first step in thecalibration procedure, the ultraviolet tube or lamp 34 is burnedcontinuously for approximately 100 hours. It has been found that theoutput of ultraviolet lamps fluctuates greatly during the initial hoursof operation of the lamp. Accordingly, by letting the lamp burncontinuously for 100 hours, the lamp's fluctuation in output can bereduced and substantially eliminated.

After the ultraviolet light has been continuously burned forapproximately 100 hours, it is necessary to measure the output of theultraviolet lamp. For that purpose, an integrating sphere and a spectralradiometer can be employed and as a result, the separate and totaloutputs of U.V.-A light, U.V.-B light and U.V.-C light can bedetermined. During measurement of the output of the ultraviolet lamp 34,the temperature in the apparatus should be maintained at a substantiallyconstant value through operation of the aforementioned ventilationsystem.

Measurements taken with a narrow band detector or sensor and a labradiometer can be standardized to the calibrated measurements and usedat a later time to determine the amount of fluctuation in the apparatus20 after, say, 6-8 months of use. As an example, say the calibratedmeasurements taken from the irradiating system output is initially 3.0watts/square meter/second (W/m² /s), using a narrow band detector andlab radiometer, the output reading can be standardized to the calibratedmeasurements. A reading from the lab radiometer reading 0.10 W/m² /swould represent 100 percent of the irradiating system's output. If, sayin six months the lab radiometer read 0.08 W/m² /s, then the systemoutput would be approximately 2.4 W/m² /s or 80 percent of the initialoperating output.

Using calibrated irradiation measurements, the total output of U.V.-Blight from the ultraviolet light source can be obtained. That output, inwatts per second, can be converted into watts per square meter persecond by dividing by the surface area of the outer cylinder or, inother words, the exposure area. It can be seen that the exposure area ofthe apparatus can be increased by utilizing an outer cylinder having alarger diameter. The addition of a layer of film such as the "KODACEL"TA 401 film mentioned above at a maximum thickness of 0.15 mm willsufficiently filter out unwanted U.V.-C light. Increasing or doublingthe maximum thickness would decrease by approximately 50 percent theamount of U.V.-B light that is transmitted through the cylinders and tothe cells in the helically wound tubing 24. Also, the amount ofirradiation can be further reduced by controlling the amount of currentsupplied to the ultraviolet lamp. An interfaced rheostat or variablepower source can be employed for effecting such a reduction inirradiation.

By knowing that the following relationships exist, the pump ratenecessary for effecting a particular irradiation of the cells in thecellular suspension can be determined. ##EQU1##

By way of example, it has been determined that in a typical bone marrowtransplant, the concentration of cells needed to rescue an allogeneicrecipient is approximately 2.3×10⁹ cells for 10 rats. Through use of anouter cylinder and inner cylinder having the dimensions noted above,utilizing a second 0.15 mm coating of "KODACEL" TA 401 on the outersurface of the inner cylinder (which further reduces the output of theultraviolet lamp by 50 percent), adjusting the power to the ultravioletlamp to thirty percent and having determined that the appropriate doseis approximately 150 J/m², it can be determined from the foregoingrelationships that the appropriate pumping rate should be approximately2.26 ml/min. when the cell concentration is about 2.3×10⁸ cells/ml.

Having determined the appropriate pumping rate, the variable rate pump80 or other suitable device is set to that rate and the cellularsuspension in the container 78 is permitted to flow into the inlet endof the tubing 24. Through the pumping action of the pump 80, thecellular suspension is fed through the tubing 24 and over the exposurearea where the cells in the cellular suspension are irradiated by theultraviolet light source. The cellular suspension flows along the lengthof the tubing and over the entire exposure area so as to be subjected tothe previously determined appropriate dosage of ultraviolet lightirradiation. The irradiated cells in the cellular suspension exit thetubing 24 at the outlet end and are collected in the collectionreservoir 82. The cells are then transplanted into the recipient.

Although the foregoing description of the apparatus and method accordingto the present invention has been described in terms of being used inconjunction with bone marrow transplants, it is to be understood thatthe apparatus and method could also be employed in other cellulartransplant and transfusion related procedures. Further it should beunderstood that other cylinders in addition to the inner and outercylinders described above could be employed.

The principles, preferred embodiments and modes of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiments disclosed. Further,the embodiments described herein are to be regarded as illustrativerather than restrictive. Variations and changes may be made by otherswithout departing from the spirit of the present invention. Accordingly,it is expressly intended that all such variations and changes which fallwithin the spirit and scope of the present invention as defined in theclaims be embraced thereby.

What is claimed is:
 1. A method of irradiating potential transplantcells with ultraviolet light through use of an apparatus comprising thesteps of:feeding a cell suspension into an inlet end of a transportmeans for transporting and guiding the cell suspension; transporting andguiding the cell suspension over at least a portion of an outerperipheral surface of an outer cylinder; irradiating the suspended cellswith ultraviolet light from an ultraviolet light source that ispositioned inside the outer cylinder; ventilating the apparatus byblowing air into a space located between an outer surface of theultraviolet light source and an inner surface of an inner cylinderpositioned between the outer cylinder and the ultraviolet light source,permitting the air to flow into a space located between an inner surfaceof the outer cylinder and outer surface of the inner cylinder, andpermitting the air to exit the apparatus; and collecting the cellsuspension after irradiation in a collection reservoir as the cellsuspension exits an outlet of the transport means.
 2. The method inaccordance with claim 1, further including the step of filtering theultraviolet light from the ultraviolet light source so that thesuspended cells are not irradiated by ultraviolet light having awavelength less than about 280 nanometers.
 3. The method in accordancewith claim 1, wherein the step of irradiating the cells with ultravioletlight includes irradiating the cells with ultraviolet light having awavelength not less than about 280 nanometers.
 4. A method ofirradiating potential transplant cells with ultraviolet light throughuse of an apparatus in order to alter antigen expression and recognitionof the cells comprising the steps of:feeding a cell suspension into aninlet end of a helically arranged transport means for transporting andguiding the cell suspension; helically transporting and guiding the cellsuspension through the transport means over at least a portion of anouter peripheral surface of an outer cylinder, the cell suspension beingtransported and guided through the transport means which is separatefrom and encircles the outer peripheral surface of the outer cylinder;altering antigen expression and recognition of the cells by irradiatingthe suspended cells with ultraviolet light from an ultraviolet lightsource that is positioned inside the outer cylinder, said cells beingirradiated with ultraviolet light having a wavelength not less thanabout 280 nanometers; and introducing the irradiated cells whose antigenexpression and recognition has been altered into a living recipient. 5.The method in accordance with claim 4, wherein the ultraviolet light isfiltered so that the cells are not subjected to ultraviolet light havinga wavelength greater than about 320 nanometers.
 6. The method inaccordance with claim 4, and further including the step of ventilatingthe apparatus by blowing air into a space located between an outersurface of the ultraviolet light source and an inner surface of an innercylinder positioned between the outer cylinder and the ultraviolet lightsource, permitting the air to flow into a space located between an innersurface of the outer cylinder and outer surface of the inner cylinder,and permitting the air to exit the apparatus.
 7. The method inaccordance with claim 4, wherein the ultraviolet light from theultraviolet light source is filtered so that the suspended cells areirradiated with ultraviolet light having a wavelength not less thanabout 280 nanometers.
 8. A method of irradiating potential transplantcells with ultraviolet light through use of an apparatus in order toalter antigen expression and recognition of the cells comprising thesteps of:feeding a cell suspension into an inlet end of a helicallyarranged transport means for transporting and guiding the cellsuspension; helically transporting and guiding the cell suspensionthrough the transport means over at least a portion of an outerperipheral surface of an outer cylinder; altering antigen expression andrecognition of the cells by irradiating the suspended cells withultraviolet light from an ultraviolet light source positioned inside aninner cylinder which is disposed within and spaced from the outercylinder, said cells being irradiated with ultraviolet light having awavelength not less than about 280 nanometers; and introducing theirradiated cells whose antigen expression and recognition has beenaltered into a living recipient.
 9. The method in accordance with claim8, further including the steps of permitting the ultraviolet lightsource to burn for a predetermined continuous period of time prior tofeeding the cell suspension into the transport means in order tostabilize the intensity and output of the ultraviolet light source andto permit calibration of the apparatus.
 10. The method in accordancewith claim 8, wherein said step of irradiating the cells includesirradiating the cells with ultraviolet light having a wavelength notgreater than about 320 nanometers.
 11. A method of inducing alterationof antigen expression and recognition of cells, comprising:providingcells from a donor source; subjecting said cells to ultravioletradiation while said cells are being conveyed through a helicallyarranged conveying means to alter antigen expression and recognition ofthe cells to the extent necessary to change immune response to thecells, said cells being subjected to ultraviolet irradiation bysubjecting the cells to ultraviolet light having a wavelength not lessthan 280 nanometers, said cells being conveyed in a helical path throughthe conveying means which is separate from and encircles an outerperipheral surface of an outer cylinder; and introducing into a livingrecipient the cells whose antigen expression has been altered throughultraviolet irradiation in order to modify antigen recognition of thetransplanted cells and thereby change immune response in the livingrecipient.
 12. The method according to claim 11, wherein said step ofsubjecting the cells to ultraviolet irradiation includes subjecting thecells to ultraviolet light that has been filtered to remove ultravioletlight having a wavelength greater than about 320 nanometers.
 13. Themethod according to claim 11, wherein said step of subjecting the cellsto ultraviolet irradiation includes subjecting the cells to ultravioletlight that has been filtered to remove ultraviolet light having awavelength less than about 280 nanometers.
 14. A method of inducingalteration of antigen expression and recognition of cells,comprising:providing cells from a donor source; subjecting said cells toultraviolet radiation while said cells are being conveyed throughconveying means to alter antigen expression and recognition to theextent necessary to change immune response to the cells, said cellsbeing subjected to ultraviolet irradiation by subjecting the cells toultraviolet light having a wavelength not less than 280 nanometers, thecells being conveyed through conveying means positioned exteriorly of anouter cylinder and being subjected to ultraviolet radiation from anultraviolet radiation source positioned inside an inner cylinder whichis disposed within and spaced from the outer cylinder; and introducinginto a living recipient the cells whose antigen expression has beenaltered through ultraviolet irradiation in order to modify antigenrecognition of the transplanted cells and thereby change immune responsein the living recipient.
 15. The method according to claim 14, whereinsaid conveying of the cells through conveying means includes conveyingthe cells through helically wound tubing while being subjected to theultraviolet irradiation.
 16. The method in accordance with claim 14,wherein said step of irradiating the cells includes irradiating thecells with ultraviolet light having a wavelength not greater than about320 nanometers.